RoamerOverland
New member
I am running 285x70x17 STT Pros and want to know what tire pressure you all are running? Can anyone please tell me what and why you are running what you are running?
Thanks!
Thanks!
Tire Pressure for 285x70x17 STT Pro
- Thread starter RoamerOverland
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Under what conditions? On pavement? I used to run mine between 38-40
Off Road anywhere from 16-25 depending on conditions. The sidewalls are pretty thick. I am sure you could go lower.
Because those tires are a bit wider than stock, you could run them a little bit below the specs on the drivers door jam --want to keep the contact patch on the road flat. But watch the tire wear pattern over time -- wear on the edges indicates too low a pressure and wear in the middle of the tire indicates too high a pressure. Other wear patterns would indicate an alignment problem or aggressive driving.
Jetboy
New member
Assuming they're E rated tires - you need to run higher pressure than P rated tires. Thicker sidewall = more heat buildup when flexing = less tire flex is required to keep heat down = you need to run higher pressure in an LT tire than you do in an P rated tire.
So as a general rule - for the same load carrying capacity of a P rated tire at 35psi - you need to run an LT tire at about 50psi.
Larger size translates to lower pressure necessary for similar load capacity.
Therefore - you should probably run your STT Pros at about 45psi or somewhere in that range is where I'd start.
So as a general rule - for the same load carrying capacity of a P rated tire at 35psi - you need to run an LT tire at about 50psi.
Larger size translates to lower pressure necessary for similar load capacity.
Therefore - you should probably run your STT Pros at about 45psi or somewhere in that range is where I'd start.
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Click on the “duratrac” link in my signature and it’ll point you to the tools to calculate a new pressure. I’m running about 38psi with 285/70r17 LTs. Yes, more rigid sidewalls are good for lateral stability when towing heavy loads, but at the same deflection in the sidewall they generate more stress, heat which turns into failure. Therefore LTs generally are run at higher pressure when on the road than a comparable P tire and give a harsher ride.
RoamerOverland
New member
Thank you all for the information. I just did a trip from SoCal to Utah/AZ (St. George and the Bar 10 Ranch at the Grand Canyon).
I found that when I set the pressure at 35psi, that after a little driving, the TPMS would read 37 to 38 psi. The tires did great on the road and the mileage was great (for me). I am concerned about running them at 38 on the highway as that would seem to cause them to grow to 40psi or so with the heat build-up. But I will give it a try.
As for offroad, I set them at 19 psi and they did great. Lots of grip in the dirt and sand of the desert. I really like these tires.
Thanks again to all for the help.
I found that when I set the pressure at 35psi, that after a little driving, the TPMS would read 37 to 38 psi. The tires did great on the road and the mileage was great (for me). I am concerned about running them at 38 on the highway as that would seem to cause them to grow to 40psi or so with the heat build-up. But I will give it a try.
As for offroad, I set them at 19 psi and they did great. Lots of grip in the dirt and sand of the desert. I really like these tires.
Thanks again to all for the help.
